Bottom Line:
In contrast, the system applied in lettuce, which itself applies pairwise comparisons using appropriate reference sets, proved functional with this species.The narrow gene pool detected in C. vulgaris may be the genetic basis for juridical conflicts between breeders.We successfully tested a methodology for identification of Essentially Derived Varieties in highly identical C. vulgaris genotypes and recommend this for future proof of essential derivation in C. vulgaris and other vegetatively propagated crops.

Background: Variety protection is of high relevance for the horticultural community and juridical cases have become more frequent in a globalized economy due to essential derivation of varieties. This applies equally to Calluna vulgaris, a vegetatively propagated species from the Ericaceae family that belongs to the top-selling pot plants in Europe. We therefore analyzed the genetic diversity of 74 selected varieties and genotypes of C. vulgaris and 3 of Erica spp. by means of RAPD and iSSR fingerprinting using 168 mono- and polymorphisms. The same data set was utilized to generate a system to reliably identify Essentially Derived Varieties (EDVs) in C. vulgaris, which was adapted from a method suggested for lettuce and barley. This system was developed, validated and used for selected tests of interest in C. vulgaris.

Results: As expected following personal communications with breeders, a very small genetic diversity became evident within C. vulgaris when investigated using our molecular methods. Thus, a dendrogram-based assay to detect Essentially Derived Varieties in this species is not suitable, although varieties are propagated vegetatively. In contrast, the system applied in lettuce, which itself applies pairwise comparisons using appropriate reference sets, proved functional with this species.

Conclusion: The narrow gene pool detected in C. vulgaris may be the genetic basis for juridical conflicts between breeders. We successfully tested a methodology for identification of Essentially Derived Varieties in highly identical C. vulgaris genotypes and recommend this for future proof of essential derivation in C. vulgaris and other vegetatively propagated crops.

Figure 2: Dendrogram consisting of 74 C. vulgaris and 3 Erica spp. genotypes. Constructed from 168 mono- and polymorphisms amplified from 13 RAPD and 5 iSSR-primers and based on the Dice/Nei and Li coefficient with subsequent UPGMA-clustering. Nodes with strong support (> 85%) by bootstrapping (n = 10.000, PHYLIP) are marked with **, moderately supported groups (50% – 85%) are marked with *, varieties of interest for the involved company are ciphered by CV# where # is replaced by increasing numbers. Variety encryption is known to the authors and the company, respectively. For purposes of clarity and according to their regional provenance, genotypes have been classified by symbols as indicated.

Mentions:
Using RAPD- and iSSR-techniques, we achieved a total of 129 (RAPD) and 39 (iSSR) distinguishable and reproducible bands. This corresponds to 9.9 bands/RAPD primer and 7.8 bands/iSSR primer. The combined results of RAPD and iSSR studies are shown in the dendrogram in Fig. 2. While the three Erica genera do cluster as an outgroup, all tested genotypes from the Calluna species cluster to the right of one node. Interestingly, the wild-types from Thuringia (Ruhla) and from the Italian Alps (San Remo) cluster as an additional outgroup within the Calluna species while the other wild-types available (Löhnstein, Niederohe, Tiefenthal, all from the Lüneburger Heide in Germany) are grouped within the rest of the Calluna genotypes.

Figure 2: Dendrogram consisting of 74 C. vulgaris and 3 Erica spp. genotypes. Constructed from 168 mono- and polymorphisms amplified from 13 RAPD and 5 iSSR-primers and based on the Dice/Nei and Li coefficient with subsequent UPGMA-clustering. Nodes with strong support (> 85%) by bootstrapping (n = 10.000, PHYLIP) are marked with **, moderately supported groups (50% – 85%) are marked with *, varieties of interest for the involved company are ciphered by CV# where # is replaced by increasing numbers. Variety encryption is known to the authors and the company, respectively. For purposes of clarity and according to their regional provenance, genotypes have been classified by symbols as indicated.

Mentions:
Using RAPD- and iSSR-techniques, we achieved a total of 129 (RAPD) and 39 (iSSR) distinguishable and reproducible bands. This corresponds to 9.9 bands/RAPD primer and 7.8 bands/iSSR primer. The combined results of RAPD and iSSR studies are shown in the dendrogram in Fig. 2. While the three Erica genera do cluster as an outgroup, all tested genotypes from the Calluna species cluster to the right of one node. Interestingly, the wild-types from Thuringia (Ruhla) and from the Italian Alps (San Remo) cluster as an additional outgroup within the Calluna species while the other wild-types available (Löhnstein, Niederohe, Tiefenthal, all from the Lüneburger Heide in Germany) are grouped within the rest of the Calluna genotypes.

Bottom Line:
In contrast, the system applied in lettuce, which itself applies pairwise comparisons using appropriate reference sets, proved functional with this species.The narrow gene pool detected in C. vulgaris may be the genetic basis for juridical conflicts between breeders.We successfully tested a methodology for identification of Essentially Derived Varieties in highly identical C. vulgaris genotypes and recommend this for future proof of essential derivation in C. vulgaris and other vegetatively propagated crops.

Background: Variety protection is of high relevance for the horticultural community and juridical cases have become more frequent in a globalized economy due to essential derivation of varieties. This applies equally to Calluna vulgaris, a vegetatively propagated species from the Ericaceae family that belongs to the top-selling pot plants in Europe. We therefore analyzed the genetic diversity of 74 selected varieties and genotypes of C. vulgaris and 3 of Erica spp. by means of RAPD and iSSR fingerprinting using 168 mono- and polymorphisms. The same data set was utilized to generate a system to reliably identify Essentially Derived Varieties (EDVs) in C. vulgaris, which was adapted from a method suggested for lettuce and barley. This system was developed, validated and used for selected tests of interest in C. vulgaris.

Results: As expected following personal communications with breeders, a very small genetic diversity became evident within C. vulgaris when investigated using our molecular methods. Thus, a dendrogram-based assay to detect Essentially Derived Varieties in this species is not suitable, although varieties are propagated vegetatively. In contrast, the system applied in lettuce, which itself applies pairwise comparisons using appropriate reference sets, proved functional with this species.

Conclusion: The narrow gene pool detected in C. vulgaris may be the genetic basis for juridical conflicts between breeders. We successfully tested a methodology for identification of Essentially Derived Varieties in highly identical C. vulgaris genotypes and recommend this for future proof of essential derivation in C. vulgaris and other vegetatively propagated crops.